Medication delivery system and monitor

ABSTRACT

Systems and methods for the delivery and monitoring of a medication, such as insulin, to a recipient are provided. An exemplary feature-rich system comprises an infusion pump with a control system for controlling medication delivery by the infusion pump and a bolus estimator for estimating an appropriate amount of medication for delivery by the control system with the infusion pump. Estimating the appropriate amount of medication for delivery is based upon one or more settings which each vary according to a setting profile. In other embodiments, the control system comprises a suspend function for temporarily suspending medication delivery by the infusion pump, an alarm profile function for programming a variable alarm volume of the alarm and a simplified menu for controlling the dual wave bolus delivery function.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming priority underSection 120 to U.S. patent application Ser. No. 12/905,629, filed Mar.Oct. 15, 2010, which is a Continuation Application claiming priorityunder Section 120 to U.S. patent application Ser. No. 11/714,552, filedMar. 6, 2007, which is a Divisional Application of U.S. patentapplication Ser. No. 10/025,052, filed Dec. 19, 2001 (now U.S. Pat. No.7,204,823, issued Apr. 17, 2007), the contents of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to systems for delivering andmonitoring medications. More specifically, this invention relates tomethods and systems for the infusion of insulin.

2. Description of the Related Art

Infusion devices and systems are well-known in the medical arts fordelivering or dispensing a medication to a patient, such as insulin to adiabetic. Generally such devices include a reservoir containing amedication for administration to the patient, an infusion pump fordispensing a medication (typically through infusion tubing and anassociated catheter) and control and monitoring systems to facilitatethe accurate delivery of the medication.

Infusion pumps typically include a small drive motor connected to areservoir piston to administer the medication to the user. Programmablecontrols can be provided for operating the drive motor continuously orat periodic intervals to obtain a closely controlled and accuratedelivery of the medication over an extended period of time. Exemplaryinfusion pumps that are used to administer insulin and other medicationsare shown and described in U.S. Pat. Nos. 4,562,751; 4,678,408;4,685,903; 5,080,653 and 5,097,122, and U.S. patent application Ser. No.09/334,858, filed Jun. 16, 1999, entitled “EXTERNAL INFUSION DEVICE WITHREMOTE PROGRAMMING BOLUS ESTIMATOR AND/OR VIBRATION ALARM CAPABILITIES”,all of which are incorporated herein by reference.

Infusion devices provide significant advantages over manualadministration by accurately delivering insulin or other medicationsover an extended period of time. Infusion devices can be relativelycompact as well as water resistant, and may thus be adapted to becarried by the user, for example, by means of a belt clip. As a result,medication can be delivered to the user with precision and in anautomated manner, without significant restriction on the user's mobilityor lifestyle, including the ability to participate in water sports.

SUMMARY OF THE INVENTION

Embodiments of the invention disclosed herein provide monitors anddelivery systems which allow for the an enhanced control of the deliveryof a medication. A typical embodiment of the present invention includesan infusion pump, a control system for controlling medication deliveryfrom the infusion pump and a bolus estimator for estimating anappropriate amount of a medication such as insulin or the like fordelivery by the control system via the infusion pump, where estimatingthe appropriate amount of the medication for delivery is based upon oneor more settings which can be varied according to a setting profile. Forexample, a control system can control medication delivery according toone or more medication delivery profiles. In preferred embodiments,medication delivery profiles are designed to optimize the delivery of anappropriate amount of insulin that is estimated by the bolus estimator.Such medication delivery profile settings can include additionalsettings relating to factors such as target blood glucose, carbohydrateratio and/or insulin sensitivity. In one embodiment, the setting profilefor at least one setting, such as target blood glucose, carbohydrateratio or insulin sensitivity, includes a value which varies according toa schedule.

In preferred embodiments of the invention, the bolus estimator estimatesthe appropriate amount of insulin based upon one or more event markersstored in a memory of the device. The one or more event markers cantrack physiological events which affect insulin need, such as meals,medication status, activities or general health. Such embodiments caninclude a wide variety of markers such as a meal marker, a snack marker,a high blood glucose marker, a low blood glucose marker, an exercisemarker, an illness marker and/or a stress marker.

Another embodiment of the invention includes a control system forcontrolling medication delivery from the infusion device. Such controlsystems can be tailored to the requirements of a specific pathology. Inan illustrative embodiment, a control system includes a suspend functionfor temporarily suspending medication delivery from the infusion device.In preferred embodiments of the invention, medication delivery iscontrolled using two or more medication delivery profiles, such as waveprofiles. Exemplary wave profiles include a square wave bolus profile, adual wave bolus profile or a basal profile. In a preferred embodiment ofthe invention, the control system includes a suspend function forseparately suspending medication delivery based on the wave profiles. Inanother embodiment, the control system further includes a resumefunction for selectively restarting a wave profile. In such systems, acompensating function can also be used for delivering a compensatingbolus to account for any suspended wave profile. The suspend functioncan further include a full suspend function for directly suspending alldelivery of a medication.

In yet another embodiment of the invention, the suspend functionincludes a menu system for selecting a period of time for temporarilysuspending medication delivery from the infusion pump. The menu systemcan include, for example, an array of fixed periods from which to selecta period of time for temporarily suspending medication delivery. Inpreferred embodiments, the menu system can also include one or moreselectable increment periods to modulate the period of time fortemporarily suspending medication delivery. In another embodiment, themenu system includes a specified time of day to select as an end of theperiod of time for temporarily suspending medication delivery. In someembodiments of the invention, after a period of time for temporarilysuspending medication delivery has concluded, the pump automaticallyresumes medication delivery.

In a related embodiment of the invention the suspend function includes ablock function for preventing delivery of medication after a potentiallyharmful amount of medication is requested by a user. The potentiallyharmfully amount of medication can result, for example, from a requestfor an unusually large bolus, a bolus requested too soon after aprevious bolus is delivered, or, alternatively, a request for too low ofa total medication dose. Such functions typically include a warningsignal to the user of the potentially harmful amount of medicationrequested. In one embodiment, the block function can be triggered insituations where a medication measurement that is integrated over anintegration period (e.g., the period of time in which a measured amountof medication is infused) exceeds a target value. In another embodiment,the block function can be triggered in situations where a secondmedication measurement that is integrated over a simultaneous andoverlapping integration period exceeds a target value. The integrationperiod can further be subdivided into a plurality of subperiods whereeach subperiod is associated with a subtotal representing medicationdelivered. In one embodiment of the invention, the oldest subtotal ofthe subperiods can be replaced by the newest subtotal of the subperiodsto, for example, identify a possible overmedication.

In yet another embodiment of the invention the infusion pump includes analarm to provide information on the status of the infusion pump and acontrol system for controlling medication delivery from the infusionpump. For example, the control system can include an alarm profilefunction for programming a variable alarm volume of the alarm. In oneembodiment, the variable alarm volume can be set by the user. In arelated embodiment, the alarm profile function varies the alarm volumeaccording to a preselected schedule.

Another embodiment of the invention includes an infusion pump and acontrol system for controlling medication delivery by the infusion pumpincluding a dual wave bolus delivery function, where the control systemincludes a conventional menu for controlling the dual wave bolusdelivery function (e.g., a menu identifying parameters associated with awave bolus delivery function which may be set by the user). In a relatedembodiment, the control system includes a conventional or simplifiedmenu for controlling the dual wave bolus delivery function (e.g., a menuidentifying one or more preset parameters associated with a dual wavebolus). Embodiments of the invention include those where the simplifiedmenu and the conventional menu can be alternately selected. In preferredembodiments of the invention, the simplified menu includes a singleentry of a total medication volume that can be divided by a preset ratiointo a first wave bolus and a second wave bolus and then delivered witha preset delay time between the first wave bolus and the second wavebolus. In other preferred embodiments of the invention, the preset ratioand preset delay time can include default values set in a pump setupmenu. The control system can also include one or more additionaldelivery functions and a default delivery mode selected in the pumpsetup menu from the dual wave bolus delivery function and/or theadditional delivery functions disclosed herein. Examples of suchdelivery functions include a square wave bolus delivery function and abasal delivery function.

In preferred embodiments of the invention, the control system isprogrammed to control medication delivery from an RF programmer, acommunication station and/or direct manual input. In another embodimentof the invention, a first device of an infusion device and RF remotepair can be used to find the second device by activating a find functionin the first device to induce an audible signal from the second device.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings in which like reference numbers representcorresponding parts throughout:

FIG. 1 is a block diagram of an exemplary infusion device embodiment ofthe invention;

FIG. 2 is a block diagram of the infusion device configured through acommunication station;

FIG. 3A illustrates fixed and variable settings of the bolus estimator;

FIGS. 3B-3D illustrate a graphical programming interface for settingprofiles;

FIG. 4 illustrates daily summaries of carbohydrate and insulin intake;

FIG. 5 illustrates detailed carbohydrate, glucose and insulininformation for a single day;

FIG. 6 is a flowchart illustrating a suspend function embodiment of theinvention; and

FIGS. 7A-7C illustrate integration plots for triggering the blockfunction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 1. Overview

Embodiments of the present invention encompass methods and systems forthe convenient operation of medication infusion devices. The descriptionprovided herein encompasses the architecture of the apparatus,associated features which optimize the control and convenience of suchdevices and methods for their utilization. Features which optimize thecontrol and convenience of the devices of the present invention may beimplemented in a wide range of infusion device designs known in the art.

A typical embodiment of the present invention includes an infusion pump,a control system for controlling medication delivery from the infusionpump and a bolus estimator for estimating an appropriate amount of amedication such as insulin or the like for delivery by the controlsystem via the infusion pump. In preferred embodiments, a function ofestimating the appropriate amount of the medication for delivery isbased upon one or more settings (e.g., a variable parameter that can beused to control the delivery of a medication) which can be variedaccording to a setting profile (e.g., a prescribed relationship betweenthe setting and a variable, such as another setting or a schedule).Typically, the control system controls medication delivery according toone or more medication delivery profiles (e.g., setting profiles for amedication delivery rate that varies according to a schedule). Inpreferred embodiments the medication delivery profiles are designed tooptimize the delivery of an appropriate amount of insulin that isestimated by the bolus estimator. In highly preferred embodiments, thesetting profile for at least one setting, such as target blood glucose,carbohydrate ratio or insulin sensitivity, includes a value that variesaccording to a schedule. In other preferred embodiments of theinvention, the bolus estimator estimates the appropriate amount ofinsulin based upon one or more event markers stored in a memory of thedevice (e.g., the recordation of when a earlier bolus was administered).

FIG. 1 illustrates a typical infusion device 100 of the presentinvention. A processor 102 contained in a housing 104 of the device 100controls the operation of the infusion device 100. The processor 102,connected to internal memory 106, can be used to run programs thatcontrol the infusion device 100. The memory 106 stores programs,historical data, user defined information, settings and otherparameters. In one embodiment the memory can be a flash memory and SRAM.In alternative embodiments, the memory 106 may include other memorystorage devices such as ROM, DRAM, RAM, EPROM, and dynamic storage suchas other flash memory and magnetic media and similar devices. In oneembodiment the infusion device 100 can be programmed directly through amanual input device 108, such as a keyboard or touch screen input, builtdirectly into the device. The device 100 can include (or alternativelyinclude) programmability through commands received from a radiofrequency (RF) programmer 110 through an RF transceiver 112 built intothe device 100. Feedback from the device 100 on the status orprogramming changes are displayed on a display 114, such as an liquidcrystal display (LCD) or touch screen display, and/or audibly through aspeaker 116. The RF programmer typically includes an input device ofsome type, such as a simple keypad, and may also include a displayand/or speaker to provide feedback in a manner similar to the infusiondevice 100.

In preferred embodiments of the invention, the processor 102 can becoupled to a drive mechanism 118 that can be connected to a medicationor fluid reservoir 120 containing fluid that can be directed through anoutlet 122 in the reservoir 120 and housing 104, and then into a body ofa user through tubing and an infusion set 124. In other embodiments, theinput device 108, display 114 and/or speaker 116 can be omitted from theexternal infusion device 100, with all programming and data transferbeing handled through the RF programmer 110. In further embodiments, theinfusion device 100 can deliver fluid directly to the user withouttubing or an infusion set 124. For example, the infusion device 100 canbe located on the user's body at the infusion site.

In an illustrative embodiment of the invention, the infusion device 100can be a medication infusion pump capable of delivering insulin to adiabetic at a rate of about 0 to about 35 units/hour in basal rates andup to about 25.0 units per meal bolus of U-100 insulin. In relatedembodiments, the infusion pump delivers other concentrations of insulinand/or other medications and may operate at other rates. Alternativeembodiments of the invention can deliver other fluid compositions suchas saline, as well as fluids that include agents such as vitamins,medications, drugs, peptides, hormones, proteins, enzymes, and vaccines,or the like.

The external infusion device 100 can provide the user with an alarmsignal as a warning to indicate some situation to address such as a lowreservoir condition or low battery or some malfunction of the system(e.g., an occlusion of the outlet that restricts the delivery of thefluid). In one embodiment of the invention, the user has the choice ofan audible alarm through the speaker 116 and/or a vibration alarm 126.Alarms may start out at a low level and escalate until acknowledged bythe user. In further embodiments, both an audible alarm and a vibrationalarm 126 may be given at the same time.

Embodiments of the invention can also include a bolus estimator 128which may operate as an independent unit within the device or as aprogram run by the processor 102. The bolus estimator 128 can functionas a specialized calculator, providing values for estimating the insulinneeds of the patient and simplifying the management of theadministration of insulin to the patient. For example, some settings forthe bolus estimator 128 are a target blood glucose value, units of bloodglucose measurement (e.g., mmol/l or mg/dl), units of carbohydrate, thecarbohydrate to insulin ratio, insulin sensitivity and blood glucoselockout (a block, requiring a minimum time delay before the bolus may beadjusted to allow the previous estimate to act).

In embodiments of the present invention, profiles can be applied to awide range of settings to facilitate versatile control of the infusiondevice 100. Numerous settings govern control of the infusion device.Some settings are directed to the actual administration of medication,such as the delivery rate, blood glucose level, carbohydrate to insulinratio or insulin sensitivity. Other settings direct more mundane aspectsof the operation of the infusion device, such as alarm volume. Anyinfusion device setting can be controlled according to a profile. Asetting that uses a profile can vary according to at least one othercondition or input. For example, a setting can operate by a profile thatvaries in value according to a daily schedule. In this case, the othercondition is time. Profiles can be used to vary the medication deliveryrates (e.g., medication delivery profiles), which can be described aswaves. Although, schedule-based setting profiles are preferred, settingprofiles can also be used which vary according to other settings, suchas blood glucose (BG) or carbohydrate measurements.

Medication delivery by the infusion device 100 is preferably managedthrough the use of profiles which represent a varying medicationdelivery rate over a fixed period of time. Multiple programming optionscan be available in the infusion device 100, and preferably includes atleast two customized basal profiles, a carbohydrate (or bolus) estimator128 and an alarm clock, as well as remote and/or on-device programming.

FIG. 2 is a block diagram of the infusion device configured through acommunication station 130. A physician/educator can configure theexternal infusion device 100 through a communication station 130 toprovide or restrict access to certain programming options. In preferredembodiments, an external infusion device 100 can download storedinformation through the communication station 130. A description of acommunication station of this general type is found in U.S. Pat. No.5,376,070 to Purvis et al., entitled “DATA TRANSFER SYSTEM FOR ANINFUSION PUMP” and U.S. Pat. application Ser. No. 09/409,014, filed Sep.29, 1999 (PCT publication WO 00/18449) to Malave et al., entitled“COMMUNICATION STATION AND SOFTWARE FOR INTERFACING WITH AN INFUSIONPUMP, ANALYTE MONITOR, ANALYTE METER OR THE LIKE”, which are bothincorporated herein by reference. Such information can be used alone orin combination with information from a glucose sensor and/or a glucosemeter (not shown) to assist the user and/or the health care professionalin making intelligent therapy decisions. Moreover, the information,programs and data may be downloaded to a remote or local PC, laptop,communication station, or the like, for analysis and review by trainedprofessional through the transceiver 112. The data may also bedownloaded through a communication station 130 to a remotely locatedcomputer 132 such as a PC, laptop, or the like, over communication lines134, such as by wired, modem, wireless connection or other electroniccommunication methods.

Operation of the infusion device 100 is typically directed throughprogramming which can be derived from a variety of possible sources. Theprogramming can either be entered directly into the infusion device 100(e.g., on the input device 108), received via the RF programmer 110, ortransferred from the communication station 130 (originating, forexample, in the computer 132). In one embodiment, the infusion devicemaintains an event log in the memory 106 that includes the source ofprogramming. This information can be used to study trends in the use ofthe infusion device 100 as well as to quickly diagnose the source offlawed programming.

The external infusion device 100 can also have additional memorycapacity to allow configuring of the display during manufacturing todisplay information in several different foreign languages, and allowfor future upgrades and revisions without the requirement of a hardwarechange. For example, a PC program can enable manufacturing to select thelanguage for the pump. Languages can include English, French, Spanish,Italian, Dutch, Swedish and German. In alternative embodiments, otherlanguages can be determined based upon market selection.

2. Bolus Estimator

Physiological carbohydrate levels are a predominant, but not exclusivefactor affecting blood glucose levels. The bolus estimator 128 of theinvention (or carbohydrate estimator that estimates a bolus based oncarbohydrate consumption (CHO)) can assist the user with carbohydratecounting and in determining precise dosing adjustments to account formeals. Generally, it is sufficient to account just for thecarbohydrates. It also encourages the user to enter current bloodglucose values before using this feature, which increases compliancewith medical regimens and optimizes control of medical devices. Incertain embodiments of the invention, the bolus estimator 128 in theexternal infusion device 100 can be connected or coupled to a glucosemonitor by way of the RF programmer 110 (or other data transfermechanism) to provide direct input to the bolus estimator 128.

In preferred embodiments of the invention, the bolus estimator 128 isused to assist the external infusion device 100 user with theestimations to determine the proper bolus amount needed to cover ananticipated carbohydrate intake at meals. The bolus estimator 128 caneffect this by suggesting a bolus based on a pre-programmed carbohydrateratio that can be stored in the memory 106 of the external infusiondevice 100. The bolus estimator 128 can also take into account theuser's insulin sensitivity and the differential between the user'spre-programmed target blood glucose (BG) level and the user's current BGlevel at the time the carbohydrate estimator 128 is activated. In thiscontext, the recommendation, or result of the bolus estimator 128, issometimes referred to as a “correction bolus”.

The bolus estimator 128 is generally activated by the user or the healthcare professional in a setup menu of the external infusion device 100,before it is operational, and preferably after the user has demonstrateda sufficient understanding of how to estimate carbohydrate intake. Inpreferred embodiments, the bolus estimator 128 is activated andprogrammed by using the input device 108 on the external infusion device100. In some embodiments, the bolus estimator 128 may be alternatelyprogrammed and activated with an RF programmer 110. In otherembodiments, the current glucose readings for the user can be providedby receipt of the medication level measurement from a glucose monitor orvia the RF programmer 110 to facilitate a correction for changing bloodglucose (BG) levels. Descriptions of correcting infusion rates based onblood glucose readings may be found in U.S. Pat. No. 5,569,186 to Lordet al., entitled “CLOSED LOOP INFUSION PUMP SYSTEM WITH REMOVABLEGLUCOSE SENSOR,”; U.S. Pat. No. 5,665,065 to Colman et al., entitled“MEDICATION INFUSION DEVICE WITH BLOOD GLUCOSE DATA INPUT”; and U.S.patent application Ser. No. 09/334,858, filed Jun. 16, 1999 and entitled“EXTERNAL INFUSION DEVICE WITH REMOTE PROGRAMMING BOLUS ESTIMATOR ANDVIBRATION ALARM CAPABILITIES”; which are all herein incorporated byreference.

In alternative embodiments of the invention, the user may be able to useother combinations of the values to identify different bolus types andamounts. In other embodiments, the bolus estimator 128 can be used in aclosed-loop system to augment the readings or check the closed-loopsystem's capability based on carbohydrate estimated meals. In otherembodiments, the bolus estimator 128 may be used to calculate correctionboluses based on other parameters, with the type of bolus correctionsbeing determined by the medication being infused, physiologicalcharacteristics of the user or the like. Preferably, the bolus estimator128 uses stored values or parameters related to the individual andcurrent values, parameters or measurements applied to an algorithm toprovide a recommended bolus that can be accepted, modified or rejectedby the user. For instance in situations of premature labor in pregnancy,the measurement of the contraction rate may be used to suggest a bolusof tocolysis medication. In HIV, a bolus amount of medication beinginfused may be adjusted based on a relationship to the current viralloads in the patient. In stroke or cardiac cases, the coagulation ratemay be used to determine the bolus amount of heparin to be administered.Other calculations may be made and the invention is not limited to theabove-described examples.

After the bolus estimator 128 has been enabled, the user can be promptedto store values for the following properties in the memory 106 of theexternal infusion device 100: the target blood glucose, insulinsensitivity and the carbohydrate ratio. In alternative embodiments, moreor fewer properties may be needed or used by the bolus estimator 128.These values are used by the bolus estimator 128 and the processor 102of the external infusion device 100 to perform the necessarycalculations in suggesting a bolus amount. In preferred embodiments,access to programming and changing these values may be restricted to ahealth care professional. In other embodiments, these values can berestricted to entry through an RF programmer 110 or a connection of theexternal infusion device 100 with a programming device, such as a PC,laptop or the like. Examples of inputted values to be stored for thebolus estimator 128 are provided below.

Target blood glucose (Target) is the target blood glucose (BG) that theuser would like to achieve and maintain. Generally, the programmableblood glucose (BG) values for this range are between 60 to 200 infive-unit increments. Preferably, the carbohydrate calculator has thecapability to accept values that; range between 20 to 600 in 1-unitincrements to cover a large number of possible scenarios. In alternativeembodiments, different ranges and increments may be used.

Insulin sensitivity (Set Sens) is a property that reflects how far theuser's blood glucose drops in milligrams per deciliter (mg/dl) when oneunit of insulin is taken. Typically, the programmable values for thisrange are between 5 to 180 in one unit increments. However, inalternative embodiments, different ranges and increments may be used. Inother embodiments, insulin sensitivity can be programmable for multipledifferent time periods (e.g., up to four different periods), the use ofwhich can require multiple separate profiles to be stored in the memory106. Setting the Insulin sensitivity profiles can be similar to settingthe basal profiles. In alternative embodiments, more or fewer timeperiods (and corresponding profiles) may be used.

The carbohydrate ratio (Set Carbs) is a value that reflects the amountof carbohydrates that are covered by one unit of insulin. Generally, thevalues are in the range of 1 to 300 in increments of 1 unit (or,alternatively, in ranges of 0.1 to 5.0 in increments of 0.1 forcarbohydrate exchanges). Preferably, the programmable values for thisrange are between 5 to 30 in one unit increments. However, inalternative embodiments, different ranges and increments can be used.

As a safety precaution, the user or healthcare professional may also seta Lockout Period, which takes into account the pharmacokinetic effect ofinsulin when suggesting a bolus. The purpose is to prevent a successiveuse of a correction bolus when the pharmacokinetic effects of theprevious bolus have not yet been accounted for. The programmable valuesfor this range are between 30 minutes to 240 minutes, programmable in 15or 30 minute increments. However, in alternative embodiments, differentranges and increments may be used. In further alternative embodiments,the lock out period may be automatically calculated based on bolusesrecently delivered and/or canceled based on new blood glucose (BG)readings. In other embodiments, the carbohydrate calculator 118 mayinclude a programmable reminder to check the post-prandial blood glucosevalue to determine if additional boluses and or corrections should bemade at a later time after the meal. The programmable reminder valuesare between 30 minutes to 240 minutes, programmable in 15 or 30 minuteincrements. In alternative embodiments, different values and incrementsmay be used.

After the properties are set in the memory 106 of the external infusiondevice 100, the bolus estimator 128 can suggest a bolus based on theentry of the estimated carbohydrate intake and current and target bloodglucose (BG) levels. The calculation can be performed using the threeproperties programmed and stored in the memory 106. Preferredembodiments use the following equation:

${Bolus} = {\frac{{{Current}\mspace{14mu} {BG}} - {{Target}\mspace{14mu} {BG}}}{{Insulin}\mspace{14mu} {Sensitivity}} + \frac{{Carbohydrates}\mspace{14mu} {to}\mspace{14mu} {be}\mspace{14mu} {Consumed}}{{Carbohydrate}\mspace{14mu} {Ratio}}}$

In contexts where the user wishes the external infusion device 100 tosuggest a bolus for the estimated carbohydrate intake only, then theonly value to program is the carbohydrate ratio, and the BG portion ofthe equation can be ignored. In alternative embodiments, variations ordifferent equations can be used.

In operation, once the bolus estimator 128 has been enabled and theabove listed values have been programmed into the memory 106 of theexternal infusion device 100, the bolus estimator 128 can be used tosuggest a correction or meal bolus. The user may then accept or changethe bolus amount suggested by the bolus estimator 128. In oneembodiment, processor 102 stores in memory 106 a record of whether thesuggested bolus amount from the bolus estimator 128 was accepted orchanged by the user, and records the suggested and changed bolusamounts. The stored data can be used for later analysis by downloadingthe data to a computer by wired, RF or IR transmissions, for example byIR transmissions from the external infusion device 100 through acommunication station to the computer, or the like as previouslydescribed.

Some embodiments of the invention employ a normal bolus. In alternativeembodiments, the user may be given the choice of a normal, dual, squarewave bolus, extended bolus, profiled bolus, or the like, by enablingthese capabilities on the variable bolus menu in the setup menu on theexternal infusion device 100. If the variable bolus capability is notenabled, then every bolus would be a normal bolus. Preferred embodimentsof the present invention use normal one-time boluses. However,alternative embodiments may utilize different bolus types to spread outthe correction or meal bolus determined by the bolus estimator 128.

Since the external infusion device 100 stores the time of each bolusdelivery, simple algorithms as illustrated above can be designed to takeinto account the amount of insulin that might still be remaining in theuser's body from a previous bolus. The longer the programmed time forthe “Insulin Duration Factor” then the more conservative the estimatebecomes. In other embodiments, the external infusion device 100 canadjust for several boluses that were delivered within the insulinduration window. Although it is difficult to absolutely predict how longinsulin will actually remain active in the body, the above-describedalgorithm does at least consider the effects on the amount of insulinactually needed. This provides an additional level of conservativeestimation in the external infusion device 100 by accounting for insulindelivered within a programmable window. Without such an algorithm, theinfusion device 100 could suggest a larger bolus than required becausethe remaining insulin might not have been accounted for in the suggestedbolus.

The bolus estimator 128 has the advantage of prompting the user to enterhis/her blood glucose (BG) value, and thus also serves as a usefulreminder to check BG levels regularly. This makes testing moreadvantageous, since the results directly assist the user in maintainingcontrol of the patient's condition. Also, the bolus estimator 128enables the external infusion device 100 to capture information oncarbohydrate intake which is valuable for helping the user to refinecarbohydrate counting skills. This data may also be downloaded to a PC,laptop, communication station, RF programmer, or the like and applied toprograms to provide an advanced analysis of the patient's insulin needs.

In other embodiments, an external infusion device 100 and user canutilize the bolus estimator 128 information to “learn” insulinsensitivity values, carbohydrate counting, the effects of high fat mealsand other variables that can lead to better control, and use this toadjust the results of the bolus estimator 128. In alternativeembodiments, the user can omit entering specific carbohydrate amountseach time calculations are made by the user. For example, the externalinfusion device 100 may store the carbohydrate amounts for several mealsthat are regularly eaten by the user in the memory 106, and then allowthe user to recall the stored meals. In other alternative embodiments, alist of general foods to may be provided with a carbohydrate equivalent.In other embodiments, the external infusion device 100 may utilize amore complicated keypad and/or RF programmer 110, and a code can beassigned for each food. Then the code for each food to be consumed canbe entered into the external infusion device 100.

FIG. 3A illustrates how the settings 300 of the bolus estimator 128 maybe fixed or variable. One or more of these settings (e.g., thecarbohydrate ratio, target blood glucose and insulin sensitivity), canfollow a profile that changes over the course of a day. FIG. 3A showsexample profiles for the carbohydrate ratio 302 and insulin sensitivity304 values that vary over a daily schedule. Using these profiles enablesthe bolus estimator 128 to provide a more accurate estimate of theappropriate amount of insulin for a patient at a given moment. Differentprofiles can also be used for different days. In general, profiles canbe generated to account for the anticipated activities of the patientwhich affect the medication needs of the patient. For example, a workdayprofile may be different than a weekend day profile. Days during whichthe patient plans to exercise can have a different profile than daysspent at rest. In addition profiles can also be created for differentlengths of time. For example, a weeklong profile can be created around apatient's default routine. Short duration profiles to accommodateunplanned activities can then be inserted as necessary.

The bolus estimator 128 can store values of current BG, carbohydrates tobe consumed and the estimated and actual bolus size and type which canbe used to provide valuable information to the user. This data of thebolus estimator 128 can be used to develop an understanding of how timeof day and other global effects should be accounted for in using theestimator 128. For example, the data can be used to calculate improvedvalues for the carbohydrate ratio and the insulin sensitivity. The dataaccumulated by the estimator includes a record of insulin delivery aswell as blood glucose measurements.

FIGS. 3B-3D illustrate a graphical programming interface for settingprofiles. In some embodiments of the invention, profiles can be setusing a convenient and efficient graphical interface. Using theinterface a profile description 306 is shown in graphical form. Thedescription 306 is composed of a series of discrete setting divisionsfor the particular parameter being programmed. The user begins by movingan indicator (e.g., a flashing division) from one end of the profiledescription 306 until he arrives at the first division 308 in theprofile that he wishes to modify. At this division, the user indicates(e.g., using an up and down arrow selector) the desired value for theparticular first division 308. In response, the interface automaticallyapplies an identical value to the subsequent division in the profiledescription 306. In other words, each following division is set at thesame level as the adjusted division. See FIG. 3B. Following this theuser begins to move the indicator to the next division 310 that hewishes to adjust from the setting of the first division 308. Allintervening divisions will retain the setting of the first division 308.See FIG. 3B. This division 310 is now adjusted and again all subsequentdivisions are adjusted to match. Prior divisions in the profile,however, remain unchanged from the setting of the first division 308. Asshown in FIG. 3D, the process can be repeated by moving the indicatoronward and setting subsequent divisions (e.g., division 312). Becausethe user is not required to enter a setting for every division in theprofile description, the graphical interface enables a user to quicklyenter a desired profile without tedious and repetitive effort. Inaddition the graphical interface can also display the time, settingvalue or rate and total for the programmed profile. It should be notedthat this graphical interface can be used for setting any parameter thatuses a profile (e.g., carbohydrate ratio, insulin sensitivity as well asbolus profiles which will be detailed hereafter).

FIGS. 4 and 5 illustrate, respectively, exemplary daily detail andsummary screens for bolus estimator use and carbohydrate intake in ananalysis program. FIG. 4 illustrates daily summaries of carbohydrate andmedication intake. FIG. 5 illustrates detailed carbohydrate, glucose andinsulin information for a single day. Use of the bolus estimator canalso be tracked in the detail and summary screens. This information canbe used to monitor patient use of the bolus estimator as well as improvethe accuracy of the bolus estimator function.

FIG. 4 illustrates a daily summary report screen. This report provides asummary of information relating to the glucose data status and insulindata status for a particular day. Alternatively, it may provide a reportfor several days in a summary format as shown. The glucose data statussection shows the number of readings, the average glucose value and therange. The insulin data status section shows total amount of insulintaken, the number of boluses, the number of bolus estimates, thecarbohydrate use, the prime volume, the percent of the time that atemporary basal rate was used, and the percent of time that the infusionpump operation was suspended.

FIG. 5 illustrates a daily detail report screen. This report provides adetailed daily view of infusion pump, glucose meter, and sensor (e.g.,monitor) data. Each screen represents a single day's data and includesthe following components: infusion pump data (e.g., insulin usage data),sensor and meter data (e.g., glucose data), alarm/event/marker table(e.g., including carbohydrate intake events) and pie charts (basal:bolusratio and bolus type).

Carbohydrate intake is graphically shown in the upper section andindicates when and how much carbohydrate consumption has occurred. Thegraph is derived from carbohydrate consumption events (such as indicatedby meal or snack markers) from the event marker table that have beenlogged by the user. The event markers can be logged into the pump andstored for later downloading or entered directly into the runningsoftware program. The exemplary event marker table is shown in the upperside section of the report screen and is further detailed below.

The infusion pump data is shown in the middle section and graphicallydepicts basal rate, bolus, prime, and alarm history for the specifiedday. The basal rate is shown as a line indicating: normal basal rate,temporary basal rate, auto-off, and suspend (e.g., the programmed normalbasal rate can be shown as a dashed line during any of: suspend,temporary basal rate, or auto-off). Boluses delivered can also beindicated. The alarm markers will be positioned to show the time of anyalarm. In the illustrated report, two insulin scales are marked due tothe relative scale of a bolus (large) compared to a basal rate (small).The bolus scale shall be on the left y-axis and the basal scale shall beon the right hand y-axis. In particular embodiments, any priming eventswill also be shown. Pie chart data is shown in a lower side section andgraphically depicts basal:bolus ratio and bolus type as pie charts.

The sensor and meter data is shown in the lower section and graphicallydepicts meter readings and sensor data -vs.- time for the specified day.Any continuous glucose monitor (i.e., sensor) readings can be displayedas a continuous line graph. Meter readings can be marked as either areference value or as calibration points. Any sensor event markers, suchas small rectangular markers, or the like, at the bottom edge shalldepict sensor event markers.

The alarm/event/marker table is shown in an upper side section and willbe shown only if either infusion pump, glucose meter, glucose monitor(i.e., sensor) or carbohydrate consumption data are present. Alarms andevents from the infusion pump, glucose meter and glucose monitor can belisted in order of time of the event/alarm. Textual definitions forevents shall be listed if defined; otherwise a numeric value for theevents shall be shown. For example, the table can display the followingevents involving programming changes for the current day: Time/Datechange—displays new date (in mm-dd-yy format) and new time, where thetime change is displayed in either 12 or 24 hr format depending onuser's settings; Suspend On/Off—time the feature was turned on and wastime turned off; Temporary basal rate—displays setting of a TemporaryBasal Rate including amount in units per hour (e.g. 0.6 u/h) andduration displayed in same format as duration for bolus history; BasalRate change—a note referring to a Basal Profile section for basal ratechange history; battery removal/replacement—displays the removal andsubsequent replacement of batteries with time of action; Maximum BasalRate change—changes of the setting along with the time of action;Maximum Bolus change—displays the change of setting along with the timeof action; Insulin Concentration change—displays the change ofconcentration; Auto Off Change—displays new feature setting along withthe time of change displayed in hours; Alarm/Error Code—briefdescription of the alarm/error.

Furthermore, a variety of additional event markers can be stored in theevent log in the memory 106 of the infusion pump. Markers can identifyany significant events (beyond mere programming changes) which relate tothe administration of medication to a particular patient and can beuseful in improving dosage estimating. For example, a meal marker canidentify a significant carbohydrate intake and a snack marker canidentify a less significant intake. Any range of markers indicating arange of carbohydrate intake values can be used. Markers can also beused to indicate low or high BG values. Exercise, illness and stress,which also affect appropriate medication dosage, can also be trackedwith event markers. At least some of these events can be taken as inputsto the bolus estimator 128 in calculating an insulin dosage. In this waythe bolus estimator can provide a complex analysis of insulin need inreal-time for the patient based upon the most current readings anestimates of BG values. For example, the infusion device 100 can trackBG values and insulin use along with the number of hypo- and hyper-medication readings, as well as the patient response to high or low BG.In addition, the event log can be downloaded to be used in otheranalysis software to identify broader trends which can be used toimprove the bolus estimator 128 predicative abilities for a particularpatient. Thus, event markers can be used in conjunction with the pumpmemory (e.g., the memory of the bolus estimator 128) and glucose data(e.g., from a glucose sensor and meter) to provide specific and averagepre- and post-event analysis. Embodiments of the present inventionprovide a convenient way to accumulate accurate event data by capturingthe information directly in the pump.

Similar to the setting profiles (e.g., carbohydrate ratio and insulinsensitivity), medication can be delivered through the infusion deviceaccording various profiles which vary over time. For example a basalprofile represent a base level of insulin which is delivered over aperiod of time. Various bolus profiles can also be used in response tomore immediate needs of the patient, such as from eating a meal. Someexamples of bolus profiles include a square wave and a dual waveprofile. The infusion device can be programmed to deliver insulinaccording to various profiles. Details of the operation of an exemplaryinfusion device are provided in U.S. patent application Ser. No.09/334,858, filed Jun. 16, 1999, which is incorporated by referenceherein.

Although dual wave bolus delivery provides a good match to a user'sneed, the number of operations required to employ the dual bolus (aswell as other advanced infusion device operations) may limit it use bysome patients. To address this, embodiments of the present inventionemploys simplified dual wave bolus programming. Dual wave bolusprogramming is activated through a menu presented to the user.

In one embodiment of the invention, the user enters the total desiredinsulin volume and that volume is divided into the two portions of thedual wave bolus, the immediate and the delayed portions, by a predefinedratio. The ratio may be fixed as a preselected setting or adjustable asa user setting. In a further embodiment, the delay time between theimmediate and delayed portions is also predefined by a user setting. Forexample, a delay of 1-½ hours can be defined at the factory.

In another embodiment, the delivery bolus profile (e.g., dual wave,square or other) can be set such that one form can be used by default.This eliminates the need for the user to specify the bolus profile everytime.

In yet another embodiment, the user can select the level ofprogrammability with respect to the dual wave bolus. A setting of fullprogrammability can allow/require the user to program all aspects of thedual wave bolus per a traditional menu as initially described. A settingof a lower level of programmability can require some values to be inputdirectly (e.g. the ratio between the immediate and delayed portions)while other values (e.g. the delay time) are taken from stored values.The lowest level of programmability merely requires entry of the totaldesired insulin volume; other required values are taken from storedpreselected settings. Thus, with only one entry, a dual bolus can bedelivered.

It should be understood that although simplified bolus programming isdescribed here with respect to programming a dual wave bolus, simplifiedbolus programming can be applied to any bolus profile including squarewave bolus profiles.

3. Convenience Features

Other embodiments of the invention can employ a suspend function whichautomatically delivers a “take a break bolus” to allow a patient todisconnect from the infusion device 100 for a predetermined period. Thisfunction is particularly well adapted for short acting medications. Thepurpose of this capability is to deliver an extra bolus beforedisconnecting from the external infusion device 100 to make certain thatthe needed amount of medication is delivered before interrupting theadministration. This can help the user remain above the minimumtherapeutic level during an interruption of medication delivery.Preferably, four durations of an interruption of the medication infusionare used: 30 minutes; 1 hour; 1 hour and 30 minutes; and 2 hours.However, additional, or longer or shorter intervals may be used.Generally, this capability is activated in the setup menu by the healthcare specialist, who can program the dose for each of the possible timesof delivery interruptions. The dose is set based on the medication andthe condition of the user. If the health care specialist programs onlycertain durations (for example, 30 minutes and 1 hour only), the userwill only be able to take a break for those durations. In alternateembodiments, the user can set the break duration and associated dosages.In preferred embodiments, in the “take a break bolus” menu screen, theuser can program the duration of the planned interruption. The externalinfusion device 100 can then beep after the delivery of the previouslyset dose. The user can then disconnect from the external infusion device100 and can be reminded by the external infusion device 100 to reconnectwhen the time is up. Preferably, the reminder alarm can continue tosound (or vibrate) until the user reactivates the external infusiondevice 100. In alternate embodiments, the infusion device has adedicated button, touch-screen button or other method, for the user toactivate a “take a break” bolus.

Other embodiments of the invention can use a more versatile suspendfunction. For example, FIG. 6 is a flowchart illustrating a suspendfunction embodiment of the invention. Upon selecting the suspendfunction, the user is presented with a menu to select the period forsuspension. In one embodiment, predetermined intervals (e.g., ½ hour, 1hour, 2 hours, etc.) are presented to be selected as described above. Inanother embodiment, as illustrated in FIG. 6, the suspend duration canbe incremented by a predetermined amount (e.g., 15 minute or 30 minuteintervals under the “SET BASAL DELAY” menu) and then entered. Also asillustrated in FIG. 6, in yet another embodiment, the user may specify aparticular time (e.g., 12:13 PM under the “SET RESUME BASAL TIME” menu)for the pump to resume operation. The appropriate “take a break bolus”can be determined as a function of the selected time based upon settingsprovided in the setup menu.

The infusion device 100 also allows for selective suspension ofspecified functions. The infusion device can be programmed to deliver ata rate defined by a basal profile or in a bolus. A bolus can bedelivered all at once and it can also be spread over a period, such aswith the square wave or dual wave profiles. The delivery profiles canalso be simultaneously programmed into the infusion device. In thiscase, when a user wishes to suspend operation of the infusion device,the user can be given the option of activating a complete suspension orselecting which profile(s) to suspend. For example, if the user hasprogrammed the infusion device to deliver a bolus and then changes hismind, the user may want to immediately suspend the bolus (e.g., squareor dual wave), but may want to maintain the basal delivery rate. Inanother example, the user may want to suspend delivery of the basalprofile, but maintain delivery of a bolus profile.

In addition, when the user restarts the infusion device 100 after asuspended operation the user can select which profiles are to be resumedand how they shall be resumed. In one embodiment, the user can select toresume a suspended square wave or dual wave bolus to restart at thepoint it was suspended. In another embodiment, the user can select torestart the basal profile. In another embodiment, the user may alsoselect that the restarting the infusion device includes calculation anddelivery of a compensating bolus to account for the fluid missed as aresult of the suspended operation.

It is also important that suspending the operation of the infusiondevice does not require multiple operations in an emergency. Therefore adedicated button or key can be provided to directly cause fullsuspension of all pump delivery. The selective suspend functionspreviously discussed are accessed through a separate menu. A warningsignal can be provided through the speaker if a suspend function isenabled to indicate the operation status to the user. In addition, thededicated suspend key can call up the suspend menu for furtherselections by the user.

Embodiments of the present invention also allow the alarm volume to beprogrammed according to a profile. In one embodiment, the user canselect different volume levels for different time periods of the day.For example, the user may select a low volume level from 8 AM to 10 PMand a high volume level from 10 PM to 8 AM. Of course, any number ofperiods and multiple volume levels can be used. This aspect of theinvention enables users to have a desired alarm volume at a desired timewithout having to manually change the volume setting daily.

4. Safety Features

Embodiments of the present invention include a variety of safetyfeatures that assist in preventing misuse of the infusion device.Warnings, such as a screen displaying full circles, symbols, messages,color changes, flashing, a special font style, or other means used toget the user's attention, can be used to inform the user of apotentially unsafe condition. Such warnings can be used for conditionsincluding, low battery voltage, an empty or low reservoir, excessivebolus requests, an unusually large bolus request and the like.

In addition, from time to time the user can temporarily remove theinfusion device. It is important that the infusion device is notmisplaced. Using the RF remote, embodiments of the present inventionallow the user to readily identify the location of the infusion deviceby activating a transmitter in the remote and cause the infusion device,receiving the signal, to emit an audible signal through the speaker.Furthermore, the RF remote can be equipped with a speaker and, by thesame principle, the infusion device can trigger the RF remote to issuean audible signal so that the user can quickly locate the RF remote.Using either of these “find functions” of the infusion device and RFremote pair, the user can quickly locate one device with the other.

In other embodiments a “lockout function” can be included to restrictoperation of the infusion device 100. Preferred embodiments can havemultiple lockout levels, with the selection dependent upon theanticipated usage, the external infusion device model, thesophistication of the user, or the like. For example, the followinglockout levels can be used. A lockout level means that some of thefeatures of the external infusion device may not be accessible to thepatient (or user), but will be accessible to the health careprofessional or the parent of a child using the external infusion device100. Access control can be managed by requiring a password or some otherauthentication method. A lockout level of “None” (0) can let the userprogram and access all features of the external infusion device 10. Alockout level of “Setup” (1) can generally lock the user out of changingthe setup menu parameters. The user may only have access to activatedfeatures of the external infusion device 100, but can not change thepre-set parameters. The user will be able to review the settings, andonly change the lockout level with an authorizing key sequence. The onlysetup feature that will still be available is selftest. A lockout levelof “All except Suspend” (2) can only allow the user to suspend theexternal infusion device and to perform a selftest. All other featurescan be locked out. The user can be able to review the settings, and onlychange the lockout level with an authorized key sequence. Finally, the“Lockout function” can be accessed in the setup menu. A special keysequence (or code) can be required to change the lockout level. This canminimize the possibility of an unauthorized change of the lockoutlevels. In preferred embodiments, an icon (lock) can be displayed on thedisplay 114 when the external infusion device 100 is in lockout mode 1or in lockout mode 2.

Preferred embodiments of the external infusion device 100 can include aconfigurable menu that can be accessible by password through the use ofa PC, laptop, RF programmer or the like. This ability allows thephysician, or sophisticated user, to select only the external infusiondevice 100 capabilities that are required for an individual user. A“lock out” capability can enable the physician to exclude certainoptions from the user. This may be useful with new users or childrenusing the external infusion device 100.

In another embodiment, a user can enable a block function that limitsthe operation of the infusion device. The block function can be employedin situations where the patient must be supervised in using the infusiondevice, such as when the patient is a child or very elderly and there isa risk that they will inadvertently misuse the infusion device andpossibly harm themselves. Enabling the block function limits the maximumbolus delivery in some fashion. For example, in one embodiment, themaximum bolus dose and/or the maximum basal rate are limited. The blockfunction can also be set to operate by a predetermined schedule. Forexample, the block function may operate during a period when operationof the infusion device will be regularly unsupervised, such as when achild is at school.

In preferred embodiments, there can be a maximum number of externalinfusion device 100 strokes for the drive mechanism 118 that may occurin one hour based on the maximum basal rate and bolus amounts.Typically, the external infusion device 100 can sound (and/or vibrate)and the external infusion device 100 will not be able to deliver morethan ((2.5*maximum bolus)+maximum basal+1) strokes in one hour.Preferably, the external infusion device 100 will deliver medication in0.1 units volume increments (although other increments may be used). Theactual amount of insulin or medication in a given stroke depends on theinsulin or medication concentration, stroke length and deliveryreservoir diameter or cross-sectional area. In preferred embodiments,the delivery rates are scrolled by the amount of insulin per stroke. Therate delivery pattern can be calculated by dividing the number ofstrokes required for the rate into 3600 (the number of seconds in onehour). The result is the number of seconds between each stroke. The ratecan be delivered evenly over the hour, each stroke on a one-secondboundary. Rates that do not divide evenly into 3600 will not have anyaccumulating error. For example, consider a rate of 3.0 units per hourand a concentration of U-100 3.0 U/hr at U-100 will require 30 strokesper hour. This translates to a pump stroke every 3600/30=120 seconds, orone stroke every two minutes. In alternative embodiments, the drivemechanism 118 may provide for continuous flow rather than incremental orpulsed flow rates. Further alternatives may omit strokes and utilizehydraulics, pneumatics, step motors, continuous motors, or the like.

The suspend and/or block functions can be triggered by monitoring theamount of infused medication. The amount of infused medication can bedetermined by integrating the pump rate over a period of time. The pumprate can be measured by the active delivery profiles (basal, square wavebolus, dual wave bolus, etc.). The monitored period (e.g., at one hourintervals) continuously repeats itself, comparing the accumulated totalto a target limit derived from a maximum basal and maximum bolus limit.

In one embodiment of the invention, more than one integration can besimultaneously performed at staggered and overlapping intervals. Withoutsuch multiple integration operations, a potentially harmful amount ofmedication could still be delivered if its delivery spans twointegration periods.

FIGS. 7A-7C illustrate integration plots for triggering the blockfunction. FIG. 7A illustrates the integration plot 700 of the infusionrate that repeats after a fixed period. If a preselected target level(e.g., a specific over-infusion amount of insulin based on a maximumbolus and maximum basal rate) 702 is exceeded within any single period704, the block function can be enabled. FIG. 7B illustrates integrationplots 700 where the target level 702 is not exceeded in the first or thesecond period because the integration is restarted at the beginning ofthe second period. It can be seen from the extended line 706 that thetarget level would have been exceeded if medication delivery had beenintegrated over an alternate single period 708. FIG. 7C illustrates tworepeating staggered and overlapping integration plots 700, 710. The twoplots are integrated over equivalent periods 704, 708 that are out ofphase with each other. For example, the periods can be 1-hour long and30 minutes out of phase with each other. A potentially harmful dose,which would have escaped detection using only the first integration plot700, is now detected by the second overlapping integration plot 710.

It should be understood that staggered and overlapping integrationperiods are equivalently implemented by shortening the integrationperiod and storing the final total from the previous integration period.The stored value can be added to the current integration and the totalcan be checked against the target. This is true because two simultaneousintegration plots produce the same change in their respective medicationtotals. In effect, embodiments of the invention can divide the fullmonitored period into two integration subperiods

The full monitored period can be subdivided into multiple integrationsubperiods, each concluding with a final subtotal representing themedication delivered over each subperiod. The system stores the finalsubtotals of the multiple integration periods. As each new integrationperiod is concluded, the new total replaces the value of the oldeststored subperiod.

The optimum number of subperiods (i.e. the subperiod size) to use can bedetermined by proposing a hypothetical subperiod size and determiningthe total amount of medication that could possibly be delivered by theinfusion device during the hypothetical period (based upon the maximumdelivery capacity of the infusion device, for instance). If this amountcan be acceptably ignored as it is replaced as the oldest subtotal, thesubperiod size is acceptably small.

In addition, embodiments of the invention can also improve performanceof block function triggering by synchronizing the integration periodswith infusion device operation. For example, the pump may ignore anyperiod of negligible infusion prior to beginning a significantmedication infusion. The integration period can be initiated when asudden change in infusion is detected. In this way, monitoring for theblock function can be appropriately synchronized with higher infusionrates.

In another embodiment of the invention, the target level is based uponan analysis of actual infusion device use for a given patient that isincorporated into the infusion device. This dynamic target level can,for example, be based upon a historic daily average (e.g. over a week or10 days) of the maximum count of infused medication for an integrationperiod for each day. An appropriate margin can be added to the historicdaily average to obtain the dynamic target level from the historic dailyaverage. In such embodiments of the invention, the infusion devicestores values of the maximum count of medication delivered in anintegration period of each day. If, in a given integration period, atotal amount of an infused medication exceeds the dynamic target level,the suspend and/or block functions can be invoked. This dynamic targetlevel and associated monitoring provides the benefit of tracking changesin infusion use over time. For example, a weight change of the patientthat causes a gradual increase or decrease in insulin use can graduallyalter the dynamic target level.

In preferred embodiments of the invention, this dynamic target level isused instead of a typical fixed target level (e.g. one based strictlyupon a fixed maximum bolus and/or maximum basal infusion rate). Inspecific embodiments of the invention, the user can select between adynamic target level and a fixed target level. For example, in contextswhere a sufficient number of days of history have not yet accumulated soas to yield a meaningful daily average, the dynamic target level can besuperseded (even if selected) in favor of a fixed target level until asuch history is established.

The historic daily average, upon which the dynamic target level isbased, can be maintained in the infusion device memory and adjusted atthe conclusion of each day by formulae such as the following:

$T_{i} = \frac{{T_{i - 1}\left( {N - 1} \right)} + G}{N}$

where, T_(i) is the new daily average, T_(i−1) is the previous dailyaverage, N is the number of days of historic use and G is the newmaximum medication count. An appropriate margin (e.g., up to 3 standarddeviations or a percentage of the daily average) is added to the newdaily average to determine the new dynamic target level. For example,the new dynamic target level can be simply set at 20% over the dailyaverage. Alternately, embodiments of the invention can calculate astandard deviation value from the historic use to determine anappropriate margin to add to the new daily average and determine the newdynamic target level. For example, the new target level can be the newdaily average plus three standard deviations.

As can be observed from the equation above, the number of days ofhistoric use of the medication delivery system (N) influences thedetermination of the dynamic target level. In this context, theselection of N influences the responsiveness of the dynamic target levelto more recent changes in infusion use. An average level from a fewernumber of days produces a dynamic target level that changes quickly inresponse to recent use. In contrast, as the number of days of historicuse is increased, the dynamic target level is more stable and lessaffected by possibly anomalous recent fluctuations in medication use. Insuch situations, a balance can be struck between the desiredresponsiveness of the delivery device and stability in the selection ofthe appropriate number of days of historic use. In addition, calculatinga new dynamic target level the invention can disregard medication countsfor days during which a previous dynamic target level was exceeded.

The foregoing description including the preferred embodiments of theinvention has been presented for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed. Many equivalent modificationsand variations are possible in light of the above teaching.

It is intended that the scope of the invention be limited not by thisdetailed description, but rather by the claims appended hereto. Theabove specification, examples and information provide a completedescription of the manufacture and use of the apparatus and method ofthe invention. Since many embodiments of the invention can be madewithout departing from the scope of the invention, the invention residesin the claims hereinafter appended. Throughout the specification variouspatents and other references are cited. The disclosures of these areincorporated by reference in their entirety.

1. A system for delivering medication, comprising: an infusion pump; acontrol system for controlling medication delivery by the infusion pump;and a bolus estimator for estimating an appropriate amount of medicationfor delivery by the control system with the infusion pump, wherein:estimating the appropriate amount of medication for delivery is basedupon one or more settings that include insulin sensitivity and varyaccording to one or more setting profiles that can be set by a user tovary according to a daily schedule; the control system controlsmedication delivery according to one or more medication deliveryprofiles comprising the appropriate amount of medication estimated bythe bolus estimator; and the setting profile is entered with a graphicalprogramming interface.
 2. The system of claim 1, wherein the insulinsensitivity setting can be set to vary according to a plurality ofseparate setting profiles that are stored in a memory of the system. 3.The system of claim 1, wherein the control system includes a suspendfunction for temporarily suspending medication delivery by the infusionpump.
 4. The system of claim 1, wherein the one or more settings furtherinclude target blood glucose or carbohydrate ratio.
 5. The system ofclaim 4, wherein the setting profile for at least one of the one or moresettings includes a value which varies according to a schedule.
 6. Thesystem of claim 1, wherein the control system is programmed to controlmedication delivery from a source selected from the group including anRF programmer, a communication station and direct input.
 7. The systemof claim 1, wherein the bolus estimator estimates the appropriate amountof medication based upon one or more event markers stored in a memory ofthe system.
 8. The system of claim 7, wherein the one or more eventmarkers track events which affect medication need.
 9. The system ofclaim 7, wherein the one or more event markers are selected from thegroup comprising a meal marker, a snack marker, a high blood glucosemarker, a low blood glucose marker, an exercise marker, an illnessmarker and a stress marker.
 10. The system of claim 1, wherein thegraphical programming interface includes a moveable indicator elementthat is used to select a setting profile that the user wishes to modify.11. A method of delivering medication, comprising the steps of:controlling medication delivery by an infusion pump with a controlsystem; estimating an appropriate amount of medication for delivery bythe control system with the infusion pump, wherein: estimating theappropriate amount of medication for delivery is based upon one or moresettings that include insulin sensitivity and vary according to one ormore setting profiles that can be set by a user to vary according to adaily schedule; the control system delivers medication deliveryaccording to one or more medication delivery profiles comprising theappropriate amount of medication estimated by the bolus estimator; andthe setting profile is entered with a graphical programming interface.12. The method of claim 11, wherein the insulin sensitivity setting canbe set to vary according to a plurality of separate setting profilesthat are stored in a memory of the system.
 13. The method of claim 12,wherein the one or more medication delivery profiles includes theappropriate amount of medication estimated by the bolus estimator. 14.The method of claim 12, wherein the one or more settings further includetarget blood glucose or carbohydrate ratio.
 15. The method of claim 14,wherein the setting profile for at least one of the one or more settingsincludes a value which varies according to a schedule.
 16. The method ofclaim 11, wherein the control system is programmed to control medicationdelivery from a source selected from the group including an RFprogrammer, a communication station and direct input.
 17. The method ofclaim 11, wherein the bolus estimator estimates the appropriate amountof medication based upon one or more event markers stored in a memory ofthe system.
 18. The method of claim 17, wherein the one or more eventmarkers track events which affect medication need.
 19. The method ofclaim 17, wherein the one or more event markers are selected from thegroup comprising a meal marker, a snack marker, a high blood glucosemarker, a low blood glucose marker, an exercise marker, an illnessmarker and a stress marker.
 20. The method of claim 11, wherein thegraphical programming interface includes a moveable indicator elementthat is used to select a setting profile that the user wishes to modify.